Dopamine ß-hydroxylase shapes intestinal inflammation through modulating T cell activation.

BACKGROUND: Inflammatory bowel disease (IBD) is a chronic and relapsing disease characterized by immune-mediated dysfunction of intestinal homeostasis. Alteration of the enteric nervous system and the subsequent neuro-immune interaction are thought to contribute to the initiation and progression of IBD. However, the role of dopamine beta-hydroxylase (DBH), an enzyme converting dopamine into norepinephrine, in modulating intestinal inflammation is not well defined. METHODS: CD4+CD45RBhighT cell adoptive transfer, and 2,4-dinitrobenzene sulfonic acid (DNBS) or dextran sodium sulfate (DSS)-induced colitis were collectively conducted to uncover the effects of DBH inhibition by nepicastat, a DBH inhibitor, in mucosal ulceration, disease severity, and T cell function. RESULTS: Inhibition of DBH by nepicastat triggered therapeutic effects on T cell adoptive transfer induced chronic mouse colitis model, which was consistent with the gene expression of DBH in multiple cell populations including T cells. Furthermore, DBH inhibition dramatically ameliorated the disease activity and colon shortening in chemically induced acute and chronic IBD models, as evidenced by morphological and histological examinations. The reshaped systemic inflammatory status was largely associated with decreased pro-inflammatory mediators, such as TNF-α, IL-6 and IFN-γ in plasma and re-balanced Th1, Th17 and Tregs in mesenteric lymph nodes (MLNs) upon colitis progression. Additionally, the conversion from dopamine (DA) to norepinephrine (NE) was inhibited resulting in increase in DA level and decrease in NE level and DA/NE showed immune-modulatory effects on the activation of immune cells. CONCLUSION: Modulation of neurotransmitter levels via inhibition of DBH exerted protective effects on progression of murine colitis by modulating the neuro-immune axis. These findings suggested a promising new therapeutic strategy for attenuating intestinal inflammation.

Changes in Noradrenergic Synthesis and Dopamine Beta-Hydroxylase Activity in Response to Oxidative Stress after Iron-induced Brain Injury.

Noradrenaline (NA) levels are altered during the first hours and several days after cortical injury. NA modulates motor functional recovery. The present study investigated whether iron-induced cortical injury modulated noradrenergic synthesis and dopamine beta-hydroxylase (DBH) activity in response to oxidative stress in the brain cortex, pons and cerebellum of the rat. Seventy-eight rats were divided into two groups: (a) the sham group, which received an intracortical injection of a vehicle solution; and (b) the injured group, which received an intracortical injection of ferrous chloride. Motor deficits were evaluated for 20 days post-injury. On the 3rd and 20th days, the rats were euthanized to measure oxidative stress indicators (reactive oxygen species (ROS), reduced glutathione (GSH) and oxidized glutathione (GSSG)) and catecholamines (NA, dopamine (DA)), plus DBH mRNA and protein levels. Our results showed that iron-induced brain cortex injury increased noradrenergic synthesis and DBH activity in the brain cortex, pons and cerebellum at 3 days post-injury, predominantly on the ipsilateral side to the injury, in response to oxidative stress. A compensatory increase in contralateral noradrenergic activity was observed, but without changes in the DBH mRNA and protein levels in the cerebellum and pons. In conclusion, iron-induced cortical injury increased the noradrenergic response in the brain cortex, pons and cerebellum, particularly on the ipsilateral side, accompanied by a compensatory response on the contralateral side. The oxidative stress was countered by antioxidant activity, which favored functional recovery following motor deficits.

Norepinephrine and dopamine contribute to distinct repetitive behaviors induced by novel odorant stress in male and female mice.

Exposure to unfamiliar odorants induces an array of repetitive defensive and non-defensive behaviors in rodents which likely reflect adaptive stress responses to the uncertain valence of novel stimuli. Mice genetically deficient for dopamine ß-hydroxylase (Dbh-/-) lack the enzyme required to convert dopamine (DA) into norepinephrine (NE), resulting in globally undetectable NE and supranormal DA levels. Because catecholamines modulate novelty detection and reactivity, we investigated the effects of novel plant-derived odorants on repetitive behaviors in Dbh-/- mice and Dbh+/- littermate controls, which have catecholamine levels comparable to wild-type mice. Unlike Dbh+/- controls, which exhibited vigorous digging in response to novel odorants, Dbh-/- mice displayed excessive grooming. Drugs that block NE synthesis or neurotransmission suppressed odorant-induced digging in Dbh+/- mice, while a DA receptor antagonist attenuated grooming in Dbh-/- mice. The testing paradigm elicited high circulating levels of corticosterone regardless of Dbh genotype, indicating that NE is dispensable for this systemic stress response. Odorant exposure increased NE and DA abundance in the prefrontal cortex (PFC) of Dbh+/- mice, while Dbh-/- animals lacked NE and had elevated PFC DA levels that were unaffected by novel smells. Together, these findings suggest that novel odorant-induced increases in central NE tone contribute to repetitive digging and reflect psychological stress, while central DA signaling contributes to repetitive grooming. Further, we have established a simple method for repeated assessment of stress-induced repetitive behaviors in mice, which may be relevant for modeling neuropsychiatric disorders like Tourette syndrome or obsessive-compulsive disorder that are characterized by stress-induced exacerbation of compulsive symptoms.

Distribution of the Noradrenaline Innervation and Adrenoceptors in the Macaque Monkey Thalamus.

Noradrenaline (NA) in the thalamus has important roles in physiological, pharmacological, and pathological neuromodulation. In this work, a complete characterization of NA axons and Alpha adrenoceptors distributions is provided. NA axons, revealed by immunohistochemistry against the synthesizing enzyme and the NA transporter, are present in all thalamic nuclei. The most densely innervated ones are the midline nuclei, intralaminar nuclei (paracentral and parafascicular), and the medial sector of the mediodorsal nucleus (MDm). The ventral motor nuclei and most somatosensory relay nuclei receive a moderate NA innervation. The pulvinar complex receives a heterogeneous innervation. The lateral geniculate nucleus (GL) has the lowest NA innervation. Alpha adrenoceptors were analyzed by in vitro quantitative autoradiography. Alpha-1 receptor densities are higher than Alpha-2 densities. Overall, axonal densities and Alpha adrenoceptor densities coincide; although some mismatches were identified. The nuclei with the highest Alpha-1 values are MDm, the parvocellular part of the ventral posterior medial nucleus, medial pulvinar, and midline nuclei. The nucleus with the lowest Alpha-1 receptor density is GL. Alpha-2 receptor densities are highest in the lateral dorsal, centromedian, medial and inferior pulvinar, and midline nuclei. These results suggest a role for NA in modulating thalamic involvement in consciousness, limbic, cognitive, and executive functions.

The cause of eyelid ptosis, orthostatic hypotension and exercise intolerance.

To provide more insight in the delay in diagnosis and expectation of treatment adapted for the paediatrician, the data were collected from patients described with dopamine beta-hydroxylase deficiency are evaluated. More insight in clinical features of dopamine beta-hydroxylase deficiency consisting mainly of eyelid ptosis, orthostatic hypotension, hypoglycaemia and exercise intolerance, explains the delay in diagnosis of this congenital disorder, although all symptoms some more concealed are present. An increasing experience by L-DOPS, a resurrection for the patient, allows recommendations for early treatment. An explanation for the delay in diagnosis is provided together with the advice for treatment.

Association of dopamine ß-hydroxylase polymorphism rs1611115 and serum levels with psychiatric disorders in Pakistani population.

AIM: Dopamine ß-hydroxylase (DBH) is a copper-containing enzyme that has an important role in maintaining the cellular homeostasis between the two neurotransmitters, dopamine (DA) and nor-adrenaline (NA). DBH functional polymorphisms are associated with multiple neuro-psychiatric conditions and are found to alter the DBH protein levels in serum affecting DBH enzymatic activity. The current study was conducted to determine the genetic and serum levels association of DBH rs1611115 functional polymorphism with major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SHZ) in the Pakistani population. METHODS: In total n = 1097 subjects including MDD (n = 427), BD (n = 204), SHZ (n = 134) and healthy controls (n = 332), were screened for the functional polymorphism by polymerase chain reaction-restriction fragment length polymorphism. Univariate logistic regression analysis was applied and the results were adjusted for age and sex. The DBH levels in serum were determined through enzyme-linked immunosorbent assay (ELISA) and the Mann Whitney U test was applied. RESULTS: The minor allele (-1021 C > T) was found to be significantly associated with a higher risk of developing BD and SHZ in both univariable and multivariable analyses. The overall total serum concentration of DBH was comparatively raised in MDD, however, in cross-comparison DBH serum levels were found markedly higher in CC homozygotes compared to TT homozygotes within the BD group. CONCLUSION: The present study suggested a significant association of DBH rs1611115 with BD and SHZ and also the effect of rs1611115 on DBH serum levels in MDD and BD for the first time in the Pakistani population.

Association between 19-bp Insertion/Deletion Polymorphism of Dopamine ß-Hydroxylase and Autism Spectrum Disorder in Thai Patients.

Background and Objectives: Autism spectrum disorder (ASD) is a neurodevelopmental disorder the cause of which is not fully known. Genetic factors are believed to play a major role in the etiology of ASD. However, genetic factors have been identified in only some cases, and other causes remain to be identified. This study aimed to identify potential associations between ASD and the 19-bp insertion/deletion polymorphism in the dopamine beta-hydroxylase (DBH) gene which plays a crucial role in the metabolism of neurotransmitters. Materials and Methods: The 19-bp insertion/deletion polymorphism upstream of the DBH gene was analyzed for associations in 177 ASD patients and 250 healthy controls. Family-based analysis was performed in family trios of each patient using the transmission disequilibrium test to investigate the potential contributions of this DBH polymorphism to ASD. Results: The frequency of the 19-bp insertion allele was significantly higher in the patient group compared to the controls (0.624 vs. 0.556, respectively; p = 0.046). The frequency of the insertion/insertion genotype was also higher in the patient group (0.378 vs. 0.288, respectively) but without statistical significance (p = 0.110). The family-based analysis showed an association between patient families and the insertion allele when only families of male participants were analyzed (73 vs. 48 events; OR 1.521; 95% CI 1.057-2.189; p = 0.023). Conclusions: This population-based analysis found an association between the 19-bp insertion allele of the DBH gene and ASD. No association at the genotype level was found. The family-based analysis found an association between the insertion allele and ASD when the analysis was performed on male participants only, suggesting a linkage between the DBH locus and ASD.

Clinical presentation and long-term follow-up of dopamine beta hydroxylase deficiency.

Dopamine beta hydroxylase (DBH) deficiency is an extremely rare autosomal recessive disorder with severe orthostatic hypotension, that can be treated with L-threo-3,4-dihydroxyphenylserine (L-DOPS). We aimed to summarize clinical, biochemical, and genetic data of all world-wide reported patients with DBH-deficiency, and to present detailed new data on long-term follow-up of a relatively large Dutch cohort. We retrospectively describe 10 patients from a Dutch cohort and 15 additional patients from the literature. We identified 25 patients (15 females) from 20 families. Ten patients were diagnosed in the Netherlands. Duration of follow-up of Dutch patients ranged from 1 to 21 years (median 13 years). All patients had severe orthostatic hypotension. Severely decreased or absent (nor)epinephrine, and increased dopamine plasma concentrations were found in 24/25 patients. Impaired kidney function and anemia were present in all Dutch patients, hypomagnesaemia in 5 out of 10. Clinically, all patients responded very well to L-DOPS, with marked reduction of orthostatic complaints. However, orthostatic hypotension remained present, and kidney function, anemia, and hypomagnesaemia only partially improved. Plasma norepinephrine increased and became detectable, while epinephrine remained undetectable in most patients. We confirm the core clinical characteristics of DBH-deficiency and the pathognomonic profile of catecholamines in body fluids. Impaired renal function, anemia, and hypomagnesaemia can be part of the clinical presentation. The subjective response to L-DOPS treatment is excellent and sustained, although the neurotransmitter profile in plasma does not normalize completely. Furthermore, orthostatic hypotension as well as renal function, anemia, and hypomagnesaemia improve only partially.

Dopamine beta-hydroxylase and its genetic variants in human health and disease.

Dopamine beta-hydroxylase (DßH) is an essential neurotransmitter-synthesizing enzyme that catalyzes the formation of norepinephrine (NE) from dopamine and has been extensively studied since its discovery in the 1950s. NE serves as a neurotransmitter in both the central and peripheral nervous systems and is the precursor to epinephrine synthesis in the brain and adrenal medulla. Alterations in noradrenergic signaling have been linked to both central nervous system and peripheral pathologies. DßH protein, which is found in circulation, can, therefore, be evaluated as a marker of norepinephrine function in a plethora of different disorders and diseases. In many of these diseases, DßH protein availability and activity are believed to contribute to disease presentation or select symptomology and are believed to be under strong genetic control. Alteration in the DßH protein by genetic polymorphisms may result in DßH becoming rate-limiting and directly contributing to lower NE and epinephrine levels and disease. With the completion of the human genome project and the advent of next-generation sequencing, new insights have been gained into the existence of naturally occurring DßH sequencing variants (genetic polymorphisms) in disease. Also, biophysical tools coupled with genetic sequences are illuminating structure-function relationships within the enzyme. In this review, we discuss the role of genetic variants in DßH and its role in health and disease.

The Role of the Brain in the Regulation of Peripheral Organs-Noradrenaline Sources in Neonatal Rats: Noradrenaline Synthesis Enzyme Activity.

This work is aimed at studying the mechanisms of reciprocal humoral regulation of noradrenaline-producing organs in rats in the perinatal period of development. The activity of noradrenaline synthesis enzymes tyrosine hydroxylase and dopamine-beta-hydroxylase was measured in the brain and adrenal glands 48 and 72 h after the injection of immunotoxin (anti-dopamine-beta-hydroxylase-saporin) into the rat brain ventricles. It was shown that, 48 h after the immunotoxin injection into the brain, the activity of tyrosine hydroxylase in the brain decreased; however, 72 h after the injection it reached the control levels. This fact indicates that noradrenaline synthesis in the survived neurons increases. In the adrenal glands, 72 h after the immunotoxin injection into the brain, the activity of dopamine-beta-hydroxylase increased. This points to a compensatory increase in the rate of noradrenaline synthesis in the adrenal glands when the synthesis of noradrenaline in the brain is inhibited.

Dopamine-beta-hydroxylase 19-bp insertion/deletion polymorphism affects medication overuse in patients with chronic migraine.

Dopamine-beta-hydroxylase (DBH) enzyme activity is modulated at the genetic level by the presence of several polymorphisms. Among these, the 19-bp insertion/deletion (I/D) polymorphism (rs72393728/rs141116007) was investigated in several genetic association studies for its correlation with the susceptibility to develop episodic migraine, but conflicting results were achieved. In the present study we analyzed this genetic variant in a carefully characterized population of migraineurs encompassing both episodic and chronic migraine (with and without medication overuse) with the aim to perform a replication study and verify any possible correlation with migraine endophenotypes. Genotyping of the DBH 19-bp I/D polymorphism was performed on 400 migraine patients and 204 healthy individuals. The associations between genotypic frequencies and the clinical and sociodemographic features of migraineurs were then investigated. The DBH 19-bp I/D polymorphism did not correlate with migraine susceptibility or most clinical variables, with the exception of a statistically significant correlation within the subgroup of patients affected by chronic migraine were the individuals carrying the deleted (D) allele were significantly more prone to abuse in analgesics. As a result of this finding, the DBH 19-bp I/D polymorphism does not influence migraine susceptibility, but it might contribute to the development of medication overuse in patient with chronic migraine.

Association of Dopamine Beta-Hydroxylase Polymorphisms with Alzheimer's Disease, Parkinson's Disease and Schizophrenia: Evidence Based on Currently Available Loci.

BACKGROUND/AIMS: The neuropathies Alzheimer's disease (AD), Parkinson's disease (PD), and schizophrenia (SCZ) have different pathological mechanisms but share some common neurodegenerative features, such as gradual loss of neuronal structure and function. Dopamine beta-hydroxylase (DBH), a gene located in the chromosomal region 9q34, plays a crucial role in the process of converting dopamine into norepinephrine (NE). Several case-control studies have reported this pathway in the pathogenesis of AD, PD and SCZ. However, the results are controversial. METHODS: We conducted a meta-analysis to estimate the associations between polymorphisms in this gene and AD, PD and SCZ. Seven databases (PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), Wan Fang, SZ Gene and AD Gene) were searched to identify eligible studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the associations of DBH variants with AD, PD and SCZ susceptibility. RESULTS: A total of 41 studies involving 10506 cases and 15083 controls were included in our meta-analysis. The analysis results indicated that a lack of association (P > 0.05) was observed between most of the currently available DBH polymorphisms and the neurological diseases AD, PD and SCZ; however, the DBH rs1611131 (allelic model: OR = 0.889, 95% CI: 0.815 - 0.969; dominant model: OR = 0.868, 95% CI: 0.778 - 0.968), rs2283123 (allelic model: OR = 0.285, 95% CI: 0.095 - 0.862; dominant model: OR = 0.290, 95% CI: 0.094 -0.897) and rs2007153 (allelic model: OR = 2.196, 95% CI: 1.506 - 3.200; dominant model: OR = 2.985, 95% CI: 1.465 - 6.084; recessive model: OR = 2.729, 95% CI: 1.548 - 4.812) variants were shown to be significantly associated with the risk of AD (the former variant) and SCZ (the latter two variants). CONCLUSION: On the one hand, most DBH polymorphisms from the currently available loci showed no linkage to AD, PD or SCZ, indicating the lower possibility of these loci serving as genetic markers of the risks of diseases with neurodegenerative characteristics. On the other hand, the DBH rs2283123 and rs2007153 polymorphisms could have opposite effects on SCZ development in Caucasians and be more specific in Croatians, while the DBH rs1611131 minor variant might have a protective effect on AD risk in Caucasians; however, these results require further study.

Reduced noradrenergic innervation of ventral midbrain dopaminergic cell groups and the subthalamic nucleus in MPTP-treated parkinsonian monkeys.

There is anatomical and functional evidence that ventral midbrain dopaminergic (DA) cell groups and the subthalamic nucleus (STN) receive noradrenergic innervation in rodents, but much less is known about these interactions in primates. Degeneration of NE neurons in the locus coeruleus (LC) and related brainstem NE cell groups is a well-established pathological feature of Parkinson's disease (PD), but the development of such pathology in animal models of PD has been inconsistent across species and laboratories. We recently demonstrated 30-40% neuronal loss in the LC, A5 and A6 NE cell groups of rhesus monkeys rendered parkinsonian by chronic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In this study, we used dopamine-beta-hydroxylase (DßH) immunocytochemistry to assess the impact of this neuronal loss on the number of NE terminal-like varicosities in the substantia nigra pars compacta (SNC), ventral tegmental area (VTA), retrorubral field (RRF) and STN of MPTP-treated parkinsonian monkeys. Our findings reveal that the NE innervation of the ventral midbrain and STN of normal monkeys is heterogeneously distributed being far more extensive in the VTA, RRF and dorsal tier of the SNC than in the ventral SNC and STN. In parkinsonian monkeys, all regions underwent a significant (~50-70%) decrease in NE innervation. At the electron microscopic level, some DßH-positive terminals formed asymmetric axo-dendritic synapses in VTA and STN. These findings demonstrate that the VTA, RRF and SNCd are the main ventral midbrain targets of ascending NE inputs, and that these connections undergo a major break-down in chronically MPTP-treated parkinsonian monkeys. This severe degeneration of the ascending NE system may contribute to the pathophysiology of ventral midbrain and STN neurons in PD.

Involvement of dopamine beta-hydroxylase in the neuroendocrine-immune regulatory network of white shrimp, Litopenaeus vannamei.

In shrimp, the biosynthesis of catecholamines, including dopamine and norepinephrine, is required for physiological and immunological responses against stress. Dopamine beta-hydroxylase (DBH), a copper-containing monooxygenase enzyme that plays an important role in catecholamine synthesis of the neuroendocrine regulatory network, was identified in Litopenaeus vannamei. In the present study, the potential role of DBH in the immunocompetence of L. vannamei was further estimated by depleting DBH by pharmaceutical inhibition of disulfiram and a gene silencing technique of L. vannamei DBH-double-stranded (ds)RNA (LvDBH-dsRNA). Immunocompetence was evaluated following the determination of the total hemocyte count, differential hemocyte count, phenoloxidase activity, respiratory bursts, superoxide dismutase activity, phagocytic activity, and the clearance efficiency as well as the susceptibility against Vibrio alginolyticus infection. At 30-120 min after shrimp had received disulfiram, they exhibited significantly reduced total hemocyte count, phenoloxidase activity of hemocytes in hemolymph, respiratory bursts of hemocytes in hemolymph and per hemocyte, phagocytic activity, clearance efficiency, and survival ratio against V. alginolyticus infection, compared to those injected with saline. In addition, the significantly lower total hemocyte count, phagocytic activity, clearance efficiency, and resistance to V. alginolyticus infection were observed in shrimp that received LvDBH-dsRNA at 3 days post injection compared to those injected with diethyl pyrocarbonate-water or non-targeting gene-dsRNA. The DBH depleted L. vannamei revealed immunosuppression and decreased the survival ratio to V. alginolyticus infection, which indicated that DBH played a crucial role in the neuroendocrine-immune regulatory network.

The dopamine beta-hydroxylase gene polymorphism rs1611114 is associated with schizophrenia in the Chinese Zhuang but not Chinese Han population.

Schizophrenia (SCZ) is a devastating neurodevelopmental disorder. However, the mechanism underlying this highly heritable disorder remains unclear. The dopamine beta-hydroxylase (DBH) gene encodes a key metabolic enzyme of dopamine. Consequently, DBH is considered a candidate gene for SCZ. However, previous studies on its association with SCZ susceptibility have shown conflicting results. Here, we examined association between the rs1611114 polymorphism of DBH and SCZ susceptibility and related clinical symptoms. A total of 691 SCZ patients and 698 age- and gender-matched healthy controls were examined. mRNA expression levels of DBH were measured by quantitative real-time polymerase chain reaction, and the rs1611114 polymorphism was genotyped using the Sequenom MassARRAY platform. Also, the Positive and Negative Syndrome Scale (PANSS) was used to assess SCZ clinical symptoms. Our results show lower DBH mRNA expression levels in SCZ patients than healthy controls (Zhuang: p = 0.000; Han: p = 0.037). Interestingly, the rs1611114 polymorphism was significantly associated with SCZ susceptibility (overdominant model: p = 0.010) in only the Chinese Zhuang population. Furthermore, the rs1611114 polymorphism was associated with PANSS total score (allele T/C: p = 0.015) and general psychopathology score (allele T/C: p = 0.027) in Chinese Zhuang SCZ patients. These results suggest that the DBH gene may play an important role in the occurrence of SCZ. Also, rs1611114 may be associated with SCZ susceptibility and related clinical symptoms in the Chinese Zhuang but not Han Chinese population. Further studies with larger samples of different ethnicities are needed to confirm the role of DBH in SCZ.

Dopamine beta-hydroxylase participate in the immunoendocrine responses of hypothermal stressed white shrimp, Litopenaeus vannamei.

Dopamine beta-hydroxylase (DBH) plays a critical role in catecholamine (CA) synthesis of neuroendocrine regulatory network, and is suggested to be involved in the immunoendocrine responses of invertebrate against bacterial challenge. DBH has been identified in white shrimp, Litopenaeus vannamei, and further investigation on its potential function was conducted after hypothermal stress, pharmaceutical inhibition and gene silencing in the present study. Cloned DBH L. vannamei (LvDBH), belonging to the Copper type II, ascorbate-dependent monooxygenases, was characterized by a DOMON domain, a Cu2_monooxygen domain and three glycosylation sites, and its expression was abundant in thoracic ganglia and haemocytes determined by quantitative real-time PCR. The effects of hypothermal stress showed that LvDBH expression in thoracic ganglia, haemocytes and hepatopancreas as well as the DBH contents in haemocytes and dopamine (DA) and norepinephrine (NE) levels in haemolymph are obviously up-regulated. L. vannamei receiving disulfiram for 30-120 min revealed the inhibition of DBH and NE contents in haemocytes and haemolymph respectively, but high level of DA in haemolymph was noticed. Besides, a significant decrease of LvDBH expression in thoracic ganglia, haemocytes and hepatopancreas were also observed. Subsequently, LvDBH expression was successfully silenced in thoracic ganglia, haemocytes and hepatopancreas of shrimp that received LvDBH-dsRNA for 3 days, and meanwhile, a decrease of DBH contents in haemocytes accompanied by decreased levels of NE and DA in haemolymph were also observed. These results indicate that LvDBH possesses the functional domains responsible for CAs synthesis, and therefore, inhibiting DBH contents in haemocytes by disulfiram and by LvDBH-dsRNA resulted in the impaired synthesis of NE from DA in haemolymph. These also suggest that the increased release of DA and NE in haemolymph for potential modulation of physiological or immunological responses is the consequence of the upregulated LvDBH expression and DBH contents in L. vannamei exposed to hypothermal stress.

The effects of enalapril and losartan on mechanical ventilation-induced sympathoadrenal activation and oxidative stress in rats.

BACKGROUND: Mechanical ventilation (MV) is a method of maintaining appropriate gas exchange in patients who are unable to sustain adequate alveolar ventilation. While lifesaving in the short-term, prolonged MV leads to altered cardiovascular responses and enhanced lung injury, but the exact mechanism is unknown. Therefore, we investigated the involvement of the sympathoadrenergic and renin-angiotensin system in MV-induced altered cardiovascular responses. METHODS: Sprague-Dawley rats were divided into six groups: (1) spontaneous breathing (SB); (2) SB + enalapril (100 µg/kg intravenous infusion); (3) SB + losartan (100 µg/kg infusion); (4) 12 h of MV; (5) MV + enalapril; and (6) MV + losartan. After the animals were sacrificed, blood and tissue samples were collected. Tyrosine hydroxylase, dopamine beta hydroxylase, and neuropeptide Y were measured in adrenal medulla and hypothalamus, whereas AT1 was measured in lung tissues by Western blot. Norepinephrine enzyme-linked immunosorbent assay and total antioxidant capacity were assayed in plasma. RESULTS: Our findings indicated that MV increases the sympathetic activation markers in adrenal medulla and hypothalamus. Moreover, oxidative stress was increased in lung and brain tissues. Treatment with enalapril or losartan reduced the lipid peroxidation in lung and brain tissues, while preserving the tissue glutathione content and plasma antioxidant capacity. CONCLUSIONS: These data demonstrate that the inhibition of the renin-angiotensin system by enalapril or losartan may reduce the MV-induced increase in sympathetic activity markers and oxidative stress, and thus, may have a beneficial effect as adjuvant therapy.

Cell-specific expression of Cre recombinase in rat noradrenergic neurons via CRISPR-Cas9 system.

Noradrenergic neurons play a crucial role in the functioning of the nervous system. They formed compact small clusters in the central nervous system. To target noradrenergic neurons in combination with viral tracing and achieve cell-type specific functional manipulation using chemogenetic or optogenetic tools, new transgenic animal lines are needed, especially rat models for their advantages in large body size with facilitating easy operation, physiological parameter monitoring, and accommodating complex behavioral and cognitive studies. In this study, we successfully generated a transgenic rat strain capable of expressing Cre recombinase under the control of the dopamine beta-hydroxylase (DBH) gene promoter using the CRISPR-Cas9 system. Our validation process included co-immunostaining with Cre and DBH antibodies, confirming the specific expression of Cre recombinase. Furthermore, stereotaxic injection of a fluorescence-labeled AAV-DIO virus illustrated the precise Cre-loxP-mediated recombination activity in noradrenergic neurons within the locus coeruleus (LC). Through crossbreeding with the LSL-fluorescence reporter rat line, DBH-Cre rats proved instrumental in delineating the position and structure of noradrenergic neuron clusters A1, A2, A6 (LC), and A7 in rats. Additionally, our specific activation of the LC noradrenergic neurons showed effective behavioral readout using chemogenetics of this rat line. Our results underscore the effectiveness and specificity of Cre recombinase in noradrenergic neurons, serving as a robust tool for cell-type specific targeting of small-sized noradrenergic nuclei. This approach enhances our understanding of their anatomical, physiological, and pathological roles, contributing to a more profound comprehension of noradrenergic neuron function in the nervous system.

Impact of gene-by-trauma interaction in MDD-related multimorbidity clusters.

BACKGROUND: Major depressive disorder (MDD) is considerably heterogeneous in terms of comorbidities, which may hamper the disentanglement of its biological mechanism. In a previous study, we classified the lifetime trajectories of MDD-related multimorbidities into seven distinct clusters, each characterized by unique genetic and environmental risk-factor profiles. The current objective was to investigate genome-wide gene-by-environment (G × E) interactions with childhood trauma burden, within the context of these clusters. METHODS: We analyzed 77,519 participants and 6,266,189 single-nucleotide polymorphisms (SNPs) of the UK Biobank database. Childhood trauma burden was assessed using the Childhood Trauma Screener (CTS). For each cluster, Plink 2.0 was used to calculate SNP × CTS interaction effects on the participants' cluster membership probabilities. We especially focused on the effects of 31 candidate genes and associated SNPs selected from previous G × E studies for childhood maltreatment's association with depression. RESULTS: At SNP-level, only the high-multimorbidity Cluster 6 revealed a genome-wide significant SNP rs145772219. At gene-level, MPST and PRH2 were genome-wide significant for the low-multimorbidity Clusters 1 and 3, respectively. Regarding candidate SNPs for G × E interactions, individual SNP results could be replicated for specific clusters. The candidate genes CREB1, DBH, and MTHFR (Cluster 5) as well as TPH1 (Cluster 6) survived multiple testing correction. LIMITATIONS: CTS is a short retrospective self-reported measurement. Clusters could be influenced by genetics of individual disorders. CONCLUSIONS: The first G × E GWAS for MDD-related multimorbidity trajectories successfully replicated findings from previous G × E studies related to depression, and revealed risk clusters for the contribution of childhood trauma.

Electroacupuncture Analgesia Is Improved by Adenoviral Gene Transfer of Dopamine Beta-hydroxylase into the Hypothalamus of Rats.

Electroacupuncture (EA) is a modified form of acupuncture that utilizes electrical stimulation. We previously showed that EA stimulated rats were divided into responders that were sensitive to EA and non-responders that were insensitive to EA based on the tail flick latency (TFL) test. The dopamine beta-hydroxylase (DBH) gene was more abundantly expressed in the hypothalamus of responder rats than non-responder rats. To determine whether overexpression of DBH gene expression in the hypothalamus modulate EA analgesia, we constructed a DBH encoding adenovirus and which was then injected into the hypothalamus of SD rats. Microinjection of DBH or control GFP virus into the hypothalamus had no changes on the basal pain threshold measured by a TFL test without EA treatment. However, the analgesic effect of EA was significantly enhanced from seven days after microinjection of the DBH virus, but not after injection of the control GFP virus. DBH expression was significantly higher in the hypothalamus of DBH virus injected rat than control GFP virus or PBS injected rats. Moreover, expression of the DBH gene did not affect the body core temperature, body weight, motor function or learning and memory ability. Although the functional role of DBH in the hypothalamus in the analgesic effect of EA remains unclear, our findings suggest that expression of the DBH gene in the hypothalamus promotes EA analgesia without obvious side-effects.